1. Field of the Invention
The present invention relates to a method of determining conditions for complementary division of a pattern comprised by an opening formed in a stencil mask used in, for example, a lithography step of a semiconductor device and a complementary division method and a program using the same.
2. Description of the Related Art
X-ray, ion, and electron beam lithography use stencil masks. Patterns are formed in a stencil mask by openings, so donut-shaped and other hard-to-form patterns are formed by complementary division (see Japanese Patent No. 3348097, Japanese Unexamined Patent Publication (Kokai) No. 2003-45786, Japanese Unexamined Patent Publication (Kokai) No. 2002-353102, Japanese Unexamined Patent Publication (Kokai) No. 2002-260983, and Japanese Unexamined Patent Publication (Kokai) No. 2002-260992).
Stencil masks suffer from two problems. One is that an internal stress changes by the formation of an opening of a pattern in the membrane (thin film) and therefore the positions of the surrounding patterns change. Another is that there is a possibility of mask destruction due to the concentration of stress occurring due to the opening shape. The occurrence of this problem can be reduced by complementary division.
In the conventional complementary division method, however, the complementary division has been mainly performed for hard-to-form pattterns, for example, donut patterns and leaf patterns. The optimum complementary division conditions have not been proposed for other patterns such as line patterns, line-and-space patterns (LS patterns), and large area patterns which become factors causing pattern displacement and mask destruction due to stress concentration.